# CVE-2019-18425: Privilege escalation in n/a

> A 32-bit PV guest user can escalate privileges to guest kernel level due to missing descriptor table limit checks in Xen emulation.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 31 Oct 2019
- **Updated:** 5 Aug 2024
- **Also known as:** ALPINE-CVE-2019-18425, DEBIAN-CVE-2019-18425, GHSA-wfcx-xxhx-657g, UBUNTU-CVE-2019-18425

## What is CVE-2019-18425?

CVE-2019-18425 is a critical vulnerability in Debian Debian Linux, published on 31 Oct 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue was discovered in Xen through 4.12.x allowing 32-bit PV guest OS users to gain guest OS privileges by installing and using descriptors. There is missing descriptor table limit checking in x86 PV emulation. When emulating certain PV guest operations, descriptor table accesses are performed by the emulating code. Such accesses should respect the guest specified limits, unless otherwise guaranteed to fail in such a case. Without this, emulation of 32-bit guest user mode calls through call gates would allow guest user mode to install and then use descriptors of their choice, as long as the guest kernel did not itself install an LDT. (Most OSes don't install any LDT by default). 32-bit PV guest user mode can elevate its privileges to that of the guest kernel. Xen versions from at least 3.2 onwards are affected. Only 32-bit PV guest user mode can leverage this vulnerability. HVM, PVH, as well as 64-bit PV guests cannot leverage this vulnerability. Arm systems are unaffected.

Weakness: CWE-269 (Improper Privilege Management)

## Which versions are affected by CVE-2019-18425?

It affects 4 products.


Products: Debian Debian Linux, Fedoraproject Fedora, Opensuse Leap, Xen Xen.

## How do I fix CVE-2019-18425?

Apply the vendor's patch.

## Is CVE-2019-18425 being exploited?

There is no known exploitation of CVE-2019-18425 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-18425 and fix it if it is affected.

What it is: CVE-2019-18425 is a critical vulnerability in Debian Debian Linux, published on 31 Oct 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2019-18425 in the wild and no public exploit code.

Affected product: Debian Debian Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2019-18425/ (Markdown: https://insights.sbomify.com/CVE-2019-18425/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-18425
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-18425
- OSV: https://osv.dev/vulnerability/CVE-2019-18425

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-18425/
Summaries are generated and may contain mistakes; the official description above is the record.